Muffle



H. G. LEDIG MUFFLE.

APPLICATXON FILED NOV. 15, 1919.

11,358,220. Patented N0v.9,1 920.

V TORI BY Q ATTORNEYS city and county of Philadelphia,

' UNITED STA.

Es PATENT OFFICE- RICHARD G. LEDIG,1 OI PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO A. MECKY I COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENN- SYLV-ANIA.

Patented Nov. 9, 1920'.

Application filed November 15, 1919. Serial No. 33,294.

To all whom it may concern:

Be it known that I, RICHARD G. LEDIG, a citizen of the United States, residin in the Pennsylvania, have invented a new and useful Muflie, of which the following is a specification.

My invention relates to the class of mufiles for electric heaters or other purposes, and it consists of a muffle adapted to become red hot its extreme length, especially from the edges-of its ends, and so the volume of heat from the mufile is increased to that extent while the black end portions of the mufile heretofore occasioned are avoided.

It further consists of details of construction as will be hereinafter described.

The invention is satisfactorily illustrated in the accompanying drawing, but the important instrumentalities thereof may be varied, and so it is to be understood that the invention is not limited to the specific details shown and described, as long as they are within the spirit or scope of the claims.

Figure 1 represents a side elevation of a muflle embodying my invention.

Fig. 2 represents a central longitudinal section on line 2-2 Fig. 1.

Fig. 3 represents an end view thereof.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings,

1 designates the body of a muflle, the same being of cylindrical or other conventional shape and composed of porcelain or other suitable material, and 2 designates the resistance wire or thread wrappedor wound spirally thereon on the exterior surface thereof, it being noticed that said body is covered by said thread to the extreme edges of the ends of theformer, whereby the susface of the body is enveloped completely from edge to edge of the ends thereof, leaving, however, small members thereof uncovered, as will be hereinafter referred to.

The interior wall of the body 1 at the end portions thereof is taperin as at 3 from near the edges thereof to sai edges, as most plainly shown in Fig. 2.

On the opposite edges of the body are the lips 4 which project laterally therefrom as integral portions thereof and they have perforations or eyes 5 therein, it being noticed tate of that the thread 2 extends to said lips which is the only part of the body uncovered by'the same.

In each eye 5 is passed the adjacent portion of the soft iron binding wire 6 to which the-adjacent end of the thread 2 is connected by twisting or other suitable means, thus providing means for supporting the mufile at its place of service, it being evident that the wire 6 and the thread 2 are carried on to the point of electric conductivity.

It will be seen that when the thread 2, the

resistance wire, is electrically energized, as the muffle is covered by the same its entire length from edge to edge (excepting, however, the short distance of the exterior of the lips 3), it will become red hot and so produce increased heat to that extent, thus overcoming the tendency of the end portions of the body becoming black, as heretofore occasioned.

The body is hollow as well known, but the tapering portions of the inner wall thereof serve tothin the material at said portions, hence the latter will become more easily redhot, it being evident that owing to said tapering surfaces the energized wire has lessrefractory. material of the body to heat, white heat, at the ends of the body than it has in the middle of the latter.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. In a muflie, a body and an electric conducting thread thereover, said body having the extreme edges of its ends covered by said thread. i

2. A mufile consisting of a hollow body, and an electric-conducting thread thereon,

said thread extending over said body from the extreme edges of the ends thereof, the interior surface of the end portions of said body being tapered outward to said edges.

3. A mufiie comprising a hollow body member, an electric -conducting thread thereon, said hollow body member having a projection at each end thereof for the binding of the conductor to said body member with a binding wire.

RICHARD Gr. LEDIG. Witnesses:

J OHN A. WIEDERSHEIM, N. BUSSINGER. 

